Identification of Immunodominant Regions and Linear B Cell Epitopes of the gE Envelope Protein of Varicella-Zoster Virus

Abstract

The envelope proteins of varicella-zoster virus (VZV) are highly immunogenic and one of the most abundant is glycoprotein E (gE). However, its immunodominant regions and epitopes have not been identified. In this study, using human sera from individuals with recent varicella or zoster infections, we have localized antigenic sequences of gE using recombinant hybrid Ty-virus-like particles (VLPs) carrying overlapping fragments of the gE protein. gE(1-134)-VLPs (particles carrying amino acids 1-134 of gE) and, to a lesser extent, gE(101-161)-VLPs were found to be the most antigenic when tested by Western blotting and ELISA. Other fragments of gE (spanning residues 161-623) showed weak or no antigenicity. Pepscan analysis of human sera on overlapping synthetic peptides representing residues 1-135 of gE revealed that the most antigenic region was between residues 50 and 135. Three immunodominant sequences (residues 86-105, 116-135, and, to a lesser extent, 56-75) were detected using sera from both varicella and zoster patients. All sera from varicella, but not zoster, patients reacted strongly with an epitope in peptide 66-85. Other epitopes were recognized weakly by some varicella or zoster sera. More sera need to be tested to assess the potential disease specificity of these epitopes. The neutralizing monoclonal antibody (MAb) IF-B9 reacted with residues 71-90; however, another neutralizing MAb, SG1A, which bound to both gE(1-134)-VLPs and gE(101-161)-VLPs did not bind to any peptide. The identification of immunodominant sequences of gE will help toward the development of a subunit VZV vaccine.

Varicella-Zoster Virus Transcriptome in Latently Infected Human Ganglia

“…VZV ORFs 40 and 68 encode virus structural proteins. ORF 40 encodes the 155-kDa major capsid protein of VZV (18), and ORF 68 encodes glycoprotein E (14). VZV ORF 66 encodes one of the two VZV protein kinases.…”

Ability of yeast Ty-VLPs (virus-like particles) containing varicella-zoster virus (VZV)gE and assembly protein fragments to induce in vitro proliferation of human lymphocytes from VZV immune patients

“…VZV gE(1-134)-VLPs, gE(101-161)-VLPs, gE(161-233)-VLPs, AP-VLPs, and control Ty-VLPs without viral inserts were produced as described previously [Fowler et al, 1995;Garcia-Valcarcel et al, 1997b].…”

“…Antigenicity studies on VZV-VLPs using human VZV convalescent sera have demonstrated strong reactivity with gE(1-134) and gE(101-161) VLPs [Fowler et al, 1995], while some sera reacted with APVLPs [Garcia-Valcarcel et al, 1997b]. Immunogenicity studies using gE(1-134), gE(101-161), and AP-VLPs have shown the constructs to prime strong T-cell responses, with the gE-VLPs also inducing VZV neutralizing antibody responses [Garcia-Valcarcel et al, 1997a,b].…”

“…This study was performed as a preliminary investigation using the LPA, with the aim of furthering previous VZV-VLP antigenicity work [Fowler et al, 1995;Garcia-Valcarcel et al, 1997b] by determining their ability to restimulate human T-cells primed in vivo following natural VZV infection.…”

“…The VZV gE is the most abundant virion envelope protein containing important T-and B-cell epitopes [Diaz et al, 1988[Diaz et al, , 1989Arvin, 1994;Fowler et al, 1995], and while the AP is believed to be an important immunogen, there have been no reports to date regarding its role in VZV CMI [Harper, 1994;Harper and Grose, 1989]. Antigenicity studies on VZV-VLPs using human VZV convalescent sera have demonstrated strong reactivity with gE(1-134) and gE(101-161) VLPs [Fowler et al, 1995], while some sera reacted with APVLPs [Garcia-Valcarcel et al, 1997b].…”